Some new ERKNet News

Article No. 310

16  January 2020

The alliance has featured ERKNet in several news articles in recent years.

( Note : Previous news item can be found using the search function on the home page and entering “ERKNet”)

ERKNet is a continent wide programme in Europe to improve the understanding of rare kidney diseases and the treatment of those diseases.

aHUS is one of those diseases and falls within the network’s  thematic group  for Thrombotic microangioathies ( TMAs) .

The first news is that the ERKNet website has been developed to include a “patient portal” to drill down to find information about diseases, hospitals, specialist doctors and much more of interest to the patient.

This facility  supports an opportunity for pan Europe  “virtual” patient consultation as patients and their health care professionals are entitled to seek advice from any of Expert Centres  which are approved participants in the reference network. An aHUS patient in Greece , for example, can, with the support of their own clinicians, seek advice on a facet of their illness from a network expert in say Germany.

The portal can be opened by visiting the ERKNet website or using this link , click on PORTAL

Another important feature of ERKNet is its patient registry.

At the time the alliance reported on the registry last June there were 99 patients enrolled in the TMA cohort. At 14 January 2020 the number had risen to 166. There are likely to be in excess of 1000 aHUS patients in Europe maybe 10 times that other renal TMAs and the TMA Group is one of the rarest, so it is quite a recruitment logistical challenge.

ERKNet’s Dr Giulia  Bassanese has informed the alliance that of the 166 enrolled TMA  patients ,  74 are aHUS patients. A surprisingly high proportion of the TMA cohort given the substantially higher incidence and prevalence of the other two diseases HUS – 88 enrolled,  and TTP with just 4 patients.

The data held on even 74 patients is sufficient already for valid research on European aHUS.

Indeed the genetic characteristics supplied by ERKNet of this initial cohort can reveal  something about the european aHUS patient. See the table below.

These  results have been  compared with those found in the European cohort extracted from the alliance’s global poll  in 2016 i.e. 75 European patients of whom 64 had known genetic tests results.( the full european report can be seen at this link here )

Of ERKNet’s 74 patients , 23 (31%) had no explained genetic cause of aHUS which is at the higher end of the range for unexplained aHUS; and much higher than the respondents in the 2016 poll of whom only 14% had no genetic  cause reported.

Of the 40 (54%)  with a complement variant explanation, 19 (47.5%) had a CFH variant , not unexpectedly the highest, and only just less than the 50 % reported  having CFH mutation  in the  2016 survey.

The MCP/CD46 variant patients were the second highest in the ERKNet cohort with 10 (25%) of the patients enrolled, over  twice the level of 12% found in the 2016 cohort. In 2016 CFI was the second highest genetic explanation at 14% but in the ERKNet cohort there were only 3 (7.5%).

There were  small numbers for the C3 mutation in both cohorts but at 8%  the 2016  result was substantially higher than the 2(5%) in the ERKNet 2020 figures.

ERKNet categorised the remaining 6 (15%)  as “other”. It does not specify what they might be but it does not include CFB and Thrombodmodulin  of which there were none . The remainder in 2016 was CFB and “more than one variant” at 10 and 6% respectively.

The non complement mutation associated aHUS reported in the ERKNet figures included Anti FH Antibodies, 7 ( 10%) , Cblc Deficiency, 2 (2.5%) and Strepococcus pneumoniae 2 ( 2.5%). Of these only AFHA was reported in the 2016 poll at a not too far different level of  8%.

Summary and comparison  of data from ERKNet at 14 January 2020 and the 2016 Global Poll

ERKNet 2020 ERKNet 2020 Alliance 2016
No. % %
Total patients 74
Tested/Unexplained 23 31 14
Total tested /complement variant found 40 54 78
CFH 19 47.5 50
MCP/CD46 10 25 12
CFI 3 7.5 14
C3 2 5 8
Other 6 15 16
other non complement  variant explanations 7 10 8
Clbc Deficiency 2 2.5
Streptococcal P. 2 2.5

There are considerable differences between the way the two sets of data were collected. ERKNet enrol volunteers through medical centres whereas the alliance poll respondents are found via the social media. The alliance poll results also  reflect a  higher proportion of U.K. participants ( almost half) whereas ERKNet so far is predominantly mainland Europe  patients with very few aHUS patients ,if any, enrolled in the U.K.

As ERKNet recruits more and more to its Registry , hopefully with more from the U.K. include if , as it is expected that, the U.K. will continue to be an ERKNet programme co-funder following  its withdrawal from the EU. Eventually the Registry data will describe in more detail the characteristics of the “european” aHUS Patient.